/* nag_dgeqlf (f08cec) Example Program. * * Copyright 2011 Numerical Algorithms Group. * * Mark 23, 2011. */ #include #include #include #include #include #include #include int main(void) { /* Scalars */ Integer i, j, m, n, nrhs, pda, pdb; Integer exit_status = 0; /* Arrays */ double *a = 0, *b = 0, *rnorm = 0, *tau = 0; /* Nag Types */ Nag_OrderType order; NagError fail; #ifdef NAG_COLUMN_MAJOR #define A(I, J) a[(J - 1) * pda + I - 1] #define B(I, J) b[(J - 1) * pdb + I - 1] order = Nag_ColMajor; #else #define A(I, J) a[(I - 1) * pda + J - 1] #define B(I, J) b[(I - 1) * pdb + J - 1] order = Nag_RowMajor; #endif INIT_FAIL(fail); printf("nag_dgeqlf (f08cec) Example Program Results\n\n"); /* Skip heading in data file */ scanf("%*[^\n]"); scanf("%ld%ld%ld%*[^\n]", &m, &n, &nrhs); /* Allocate memory */ if (!(a = NAG_ALLOC(m*n, double)) || !(b = NAG_ALLOC(m*nrhs, double)) || !(rnorm = NAG_ALLOC(nrhs, double)) || !(tau = NAG_ALLOC(n, double))) { printf("Allocation failure\n"); exit_status = -1; goto END; } #ifdef NAG_COLUMN_MAJOR pda = m; pdb = m; #else pda = n; pdb = nrhs; #endif /* Read A and B from data file */ for (i = 1; i <= m; ++i) for (j = 1; j <= n; ++j) scanf("%lf", &A(i, j)); scanf("%*[^\n]"); for (i = 1; i <= m; ++i) for (j = 1; j <= nrhs; ++j) scanf("%lf", &B(i, j)); scanf("%*[^\n]"); /* nag_dgeqlf (f08cec). * Compute the QL factorization of A. */ nag_dgeqlf(order, m, n, a, pda, tau, &fail); if (fail.code != NE_NOERROR) { printf("Error from nag_dgeqlf (f08cec).\n%s\n", fail.message); exit_status = 1; goto END; } /* nag_dormql (f08cgc). * Compute C = (C1) = (Q**T)*B, storing the result in B. * (C2) */ nag_dormql(order, Nag_LeftSide, Nag_Trans, m, nrhs, n, a, pda, tau, b, pdb, &fail); if (fail.code != NE_NOERROR) { printf("Error from nag_dormql (f08cgc).\n%s\n", fail.message); exit_status = 1; goto END; } /* nag_dtrtrs (f07tec). * Compute least-squares solutions by backsubstitution in * L*X = C2. */ nag_dtrtrs(order, Nag_Lower, Nag_NoTrans, Nag_NonUnitDiag, n, nrhs, &A(m - n + 1, 1), pda, &B(m - n + 1, 1), pdb, &fail); if (fail.code != NE_NOERROR) { printf("Error from nag_dtrtrs (f07tec).\n%s\n", fail.message); exit_status = 1; goto END; } /* nag_gen_real_mat_print (x04cac). * Print least-squares solution(s). */ fflush(stdout); nag_gen_real_mat_print(order, Nag_GeneralMatrix, Nag_NonUnitDiag, n, nrhs, &B(m - n + 1, 1), pdb, "Least-squares solution(s)", 0, &fail); if (fail.code != NE_NOERROR) { printf("Error from nag_gen_real_mat_print (x04cac).\n%s\n", fail.message); exit_status = 1; goto END; } /* nag_dge_norm (f16rac). * Compute and print estimates of the square roots of the residual * sums of squares. */ for (j = 1; j <= nrhs; ++j) { nag_dge_norm(order, Nag_FrobeniusNorm, m-n, 1, &B(1, j), pdb, &rnorm[j-1], &fail); if (fail.code != NE_NOERROR) { printf("Error from nag_dge_norm (f16rac).\n%s\n", fail.message); exit_status = 1; goto END; } } printf("\nSquare root(s) of the residual sum(s) of squares\n"); for (j = 0; j < nrhs; ++j) printf("%11.2e%s", rnorm[j], (j+1)%7 == 0?"\n":" "); END: NAG_FREE(a); NAG_FREE(b); NAG_FREE(rnorm); NAG_FREE(tau); return exit_status; } #undef A #undef B